Bull. Soc. Chim. B e l q . vo1.92/nn 1/1983 SYNTHESE ET REACTIVITE DU [9,2-b] PYRIDINO [ 4 , 5 1 BENZO-l,3a,6,6a-TETRAAZAPENTALENE. A. MAQUESTIAU, M. FLAMMANG-BARBIEUX et E. VILAIN. Laboaatoihe de Chimie Ohganique, hiVehbi.t6? d e 1'Eta.t ir Monb. ABSTRACT. A new heteroaromatic pentalene, [3.2-b] pyridino [ 4 , 5 ] benzoil,3a,6,6a-t&traazapentalene [3] has been prepared by direct condensation of 2-chloro-3-ni-tropyridine with benzotriazole followed by reductive cyclisation of the l-(3'n i t r o -2 ' -p y r i d y l ) b e n z o t r i a z o l e intermediate with triethylphosphite. The spectral and chemical properties of this new compound are described and the positions of the introduced substituents are determined a s well by 'H NMR spectroscopy as by EHT calculations.